Preparation And Characterization Of Antibacterial Alginate/Quaternarized Chitosan Hydrogel Dressings

In recent years,hydrogel dressings have become a new modernize dressings.Compared with other types of dressings,the wet tissue contact environment,the absorption of wound exudate and the prevention of tissue adhesion are the main advantages.At the same time,antibacterial drugs loaded on hydrogel dressings can also give the antibacterial properties.For the lack of mechanical properties of existing hydrogels in the market,the poor solubility of chitosan and the limited antibacterial properties,the transparency,mechanics and antibacterial properties of hydrogel have been explored in this paper.Sodium alginate is an anion polyelectrolyte,and quaternary ammonium salt of chitosan is a cation polyelectrolyte.Because the two kinds of raw materials have different charges,the polyelectrolyte formed by two kinds of polyelectrolytes can not stabilize in solution and appear in the form of precipitate.A homogeneous system is not formed in solution blending,which makes the performance of hydrogel cannot be accurately evaluated.Therefore,in order to obtain a stable hydrogel,the primary solution of the experiment is to weak the intensity of electric charge.In order to solve this problem,two research directions were designed,one is to select low substitute quaternary ammonium salt chitosan,and the expectation is to reduce the charge strength of the raw material;the other one is that salt system is introduced as a charge block agent.In this paper,the different substitution degree of chitosan quaternary ammonium salt has been produced by alkaline pretreatment and ring-opening method of epoxides.And the changes in transparency of blending gels have been explored along with the reduction of substitution degree of quaternary ammonium chitosan simultaneously.In the test,it was found that the chitosan after pretreatment reacted 8 h under 80?,andCS:GTA= 1:2,meanwhile,It can shorten the reaction time effectively and obtain quaternary ammonium salt chitosan with better water solubility.It was found that the reduction of substitution degree was not effective in improving the transparency of the blend gel.Meanwhile,the effect of charge shielding on the transparency of the blend gel was further studied.It is shown that there is a direct connection between the amount of charge blocker and chitosan quaternary ammonium salt substibution degree.Under the same quality of chitosan quaternary ammonium salt,if the substibution degree is higher,the amount of charge blocker will be higher too when the blending solution is transparent.When the substitution degrees of chitosan quaternary ammonium salt are the 166.9%,we can achieve a transparent blending gels when the amount of charge shielding agents accounted for 3%of the blend system.The hydrogel prepared by this solution was more transparentOn the basis of it,the blending concentration,the ratio of blend,the effect of crosslinking concentration and crosslinking time on the mechanical properties,moisture absorption and water supply capacity have been further studied.It has shown the solution concentration of sodium alginate could decide the mechanical properties and morphological characteristics of blending gels directly.When the concentration of sodium alginate is 3%,the gel thickness is 2-3 mm.Crosslinking agent concentration and crosslinking time has important impacts not only on the mechanical properties but also on the moisture absorption and water supply capacity of hydrogel,and then to explore the important influencing factors of hydrogel properties.Synthesized chitosan quaternary ammonium salt is an important material in the derivative of chitosan.It not only keeps the biological properties,but also further improves the antimicrobial properties and water solubility.These properties could expand the application range of chitosan.At the same time,the study in this paper could optimize the preparation process of hydrogel,realizing the controllable production of hydrogels.